Bi. Jun et al., THE EVOLUTION OF COSMIC-RAY MEDIATED MAGNETOHYDRODYNAMIC SHOCKS - A 2-FLUID APPROACH, The Astrophysical journal, 429(2), 1994, pp. 748-758
We study the shock structure and acceleration efficiency of cosmic-ray
mediated MHD shocks both analytically and numerically by using a two-
fluid model. Our model includes the dynamical effect of magnetic field
s and cosmic rays on a background thermal fluid. The steady state solu
tion is derived by following the technique of Drury & Volk (1981) and
compared to numerical results. We explore the time evolution of plane-
perpendicular, piston-driven shocks. From the results of analytical an
d numerical studies, we conclude that the mean magnetic field plays an
important role in the structure and acceleration efficiency of cosmic
-ray mediated MHD shocks. The acceleration of cosmic-ray particles bec
omes less efficient in the presence of strong magnetic pressure since
the field makes the shock less compressive. This feature is more promi
nent at low Mach numbers than at high Mach numbers.